Which of these numbers is composite? ${7,\ 11,\ 17,\ 67,\ 77}$
Answer: A composite number is a number that has more than two factors (including 1 and itself). 7, 11, 17, and 67 each have only two factors. The factors of 77 are 1, 7, 11, and 77. Thus, 77 is the composite number.